The present invention relates to heat-exchangers, especially of the type where the one medium is constituted by a gas or by a vapor, and which comprises a plurality of elongate elements defining between themselves flow channels for the two media of the apparatus.
The main object of the invention is to provide a heat-exchanger simultaneously satisfying the requirements for high efficiency and for usefulness also in such connections where either the one medium contains substances which may have a corroding or eroding effect on the surface-extending means of the heat-exchanger, or one medium must be protected from direct contact with those means.
Another object of the invention is to provide a heat-exchanger the heat-exchanging elements of which shall be designed so as to permit low-cost manufacture in a continuous process which may, by way of example, comprise extrusion or pressing steps.